The present study seeks to examine differences in activity, opportunities for physical activity, and aspects of the built environment across rural and urban dwelling middle school children. This study will be guided by a social-ecological approach and will utilize a mixed-methods design. A social-ecological approach focuses attention on interpersonal, organizational, community, and environmental factors which support healthy behaviors. For the proposed research, a qualitative study will be conducted first which will collect data from community stakeholders, parents and their children regarding opportunities for physical activity and aspects of the built environment in one rural and one urban community. This will inform the construction of a questionnaire to assess the built environment which is appropriate for both locations. Secondly, a quantitative study will be conducted to collect objectively measured physical activity and cardiovascular fitness in 450 middle school children in the same rural (n = 225) and urban (n = 225) communities. Participating children will also provide information concerning intra-personal, inter-personal, and community level (i.e., opportunities for physical activity and aspects of the built environment) factors that are barriers and opportunities for physical activity. Finally, objective data (collected using GIS) concerning proximity to opportunities for physical activity and features of the built environment will be collected. This study will address two primary aims: 1) To compare aspects of the community environment in the form of programming and built environment that support physical activity which differ across middle school children living in an urbanized area and a rural county, and 2) To examine associations between environmental supports for physical activity and features of the built environment with cardiovascular fitness and physical activity in middle school children living in an urbanized area and a rural county. The proposed work is directly relevant to two of the CDC's overarching goals related to its core mission;1) Healthy People in Every Stage of Life, 2) Healthy People in Healthy Places by providing information pertinent to the dissemination of physical activity promoting interventions for children in rural and urban environments.